Wind or water energy installation

ABSTRACT

A wind or water energy installation for generating electrical energy, an installation having at least one propeller and at least one generator having a rotor and a stator. The stator is formed by at least two mechanically and electrically independent stator modules that co-operate respectively with the rotor, each of the stator modules respectively including at least one module-inherent magnet, and at least one coil through which at least part of the magnetic flux of the magnet flows, and each of the stator modules forms a module-inherent magnet circuit with the rotor. In the event of a relative movement between the rotor and the stator, each stator module generates a module-inherent output voltage.

The invention relates to a wind or water energy installation having the features according to the precharacterizing clause of claim 1.

For many years, electrical energy has been obtained from the wind with the aid of wind turbines, which have become ever larger. The achievable power levels are dependent, inter alia, on the diameter of the wind turbine. Higher power levels therefore also mean larger wind turbine diameters and larger propeller blade lengths. Since the circumferential speed of the propeller tips is technically limited, this results in ever lower rotation speeds.

The invention is based on the object of specifying a wind or water energy installation which can generate high electrical power levels but nevertheless is of simple and lightweight design.

According to the invention, this object is achieved by a wind or water energy installation having the features claimed in patent claim 1. Advantageous refinements of the wind or water installation according to the invention are described in dependent claims.

According to the invention, a wind or water energy installation is accordingly provided for production of electrical energy having at least one propeller and at least one generator, which comprises a rotor and a stator. The wind or water energy installation is characterized in that the stator is formed by at least two stator modules which are mechanically and electrically independent of one another and each interact with the rotor, each of the stator modules in each case comprises at least one module-specific magnet, at least one coil through which at least a portion of the magnetic flux of the magnet flows, and each of the stator modules in each case forms a module-specific magnetic circuit with the rotor, with each stator module producing a module-specific output voltage in the event of a relative movement between the rotor and the stator.

One major advantage of the wind or water energy installation according to the invention is that the stator is formed from separate stator modules; this allows particularly simple installation of the stator, in particular at a great height above the ground, as is normal for wind power installations. There is therefore no need, as in the case of already known wind or water energy installations, for the entire stator to be transported and installed in one piece for installation of the stator and in fact, it can be moved stator module by stator module to the respective installation location, and can be installed on site, for example using a crane.

A further major advantage of the wind or water energy installation according to the invention is that, in the event of a defect, individual stator modules can be replaced. There is therefore no need to replace the entire stator, thus making it possible to save costs in the event of repair.

An additional advantage of the wind or water energy installation according to the invention is that all of the components which are heated and may need to be cooled during operation of the generator in order to prevent limit temperatures from being exceeded can be arranged in the stator of the generator. Cooling of the stator from the outside is technically relatively simple, and can be carried out at low cost. Those parts and elements which carry flux, are arranged in the rotor and can be heated by remagnetization or eddy currents, and can also be heated by the stator by heat transfer and/or radiation can be formed by parts whose temperature is not critical in the case of the wind or water energy installation according to the invention, as a result of which there is no need for additional cooling. In other words, one major advantage of the wind or water energy installation according to the invention is also that only stator sections need be cooled and there is no need for cooling of the rotor, even when very high electrical power levels are produced.

The stator-side coils of the stator modules may, for example, be electrically interconnected in order to make it possible to provide the appropriate currents or voltages, depending on the configuration of the electrical power supply system to which the wind or water energy installation is connected.

The wind or water energy installation is preferably an installation which has a rating of at least 1 kW. A rating such as this is generally necessary in order to allow economic use in power transmission systems.

The stator modules are preferably designed such that they can each be removed from the generator, and fitted into it, independently of other stator modules, and can be replaced independently of other stator modules.

It is also considered to be advantageous for the stator modules each to have a mounting device by means of which the distance between the respective stator module and the rotor can be adjusted on a module-specific basis.

Preferably, at least one of the stator modules, preferably all of the stator modules, has or have a module-specific cooling device.

Furthermore, it is considered to be advantageous if the stator module has a magnetic yoke, and the module-specific cooling device is arranged indirectly or directly on that yoke outer face of the magnetic yoke which is averted from the rotor.

At least one of the stator modules, preferably all of the stator modules, has or in each case have a converter or rectifier, which converts or rectifies an AC voltage produced by the module-specific coil or coils, and produces a module-specific AC voltage or DC voltage as the module-specific output voltage.

Preferably, the converter or rectifier is arranged on an outer face of the module-specific cooling device which is averted from the rotor and the yoke outer face.

In terms of achieving low construction costs, it is considered to be advantageous for the stator modules of the stator to be physically identical.

Preferably, on its surface facing the stator modules, the rotor has a magnetic reluctance (Rm), which is dependent on its respective rotation angle, such that the magnitude of the magnetic flux in the coils of the stator modules is dependent on the respective rotation angle of the rotor, and varies during rotation of the rotor.

Preferably, the magnets of the stator modules are formed by permanent magnets. Alternatively, it is also possible to use electromagnets for production of a magnetic flux, instead of permanent magnets or in combination with permanent magnets.

Preferably, the arrangement of the stator modules around the rotation axis of the rotor is rotationally symmetrical.

By way of example, the rotor may be arranged externally around the stator or within the stator.

Preferably, a propeller of the wind or water energy installation is connected to the rotor of the generator such that they rotate together. There is therefore no need for a gearbox between the rotor and the propeller, thus minimizing the weight and costs.

In order to allow a polyphase, for example three-phase, electricity production, it is considered to be advantageous if the rotational symmetry angle of the arrangement of the stator modules of the stator and the rotational symmetry angle of the local distribution of the magnetic reluctance on the rotor are different. A rotational symmetry angle difference leads to a different pole pitch on the stator and on the rotor, thus making it possible to generate electric current for polyphase systems.

The rotational symmetry angle of the stator and that of the rotor may, of course, also be identical, if the intention is to produce only a single current and voltage phase.

Preferably, on its surface facing the stator, the rotor has teeth which extend radially outward. A tooth structure or a tooth profile makes it possible to produce a magnetic reluctance, which is dependent on the respective rotation angle of the rotor, on the surface of the rotor in a particularly simple manner. Preferably, the teeth on the surface of the rotor consist of a material having low magnetic reluctance, that is to say a material which causes a high magnetic flux when a magnetic field is applied. For example, one material which is suitable for the teeth is ferromagnetic material, since it has a very high permeability.

The intermediate space between adjacent teeth of the stator may, for example, be entirely or partially filled with a material which has a higher magnetic reluctance than the material of the teeth. For example, the intermediate space between adjacent teeth may be filled with a plastic or a resin.

However, it is considered to be particularly advantageous for the intermediate space between adjacent teeth to remain free, since, when the rotor rotates, exposed teeth lead to swirling of the air in the air gap between the stator and the rotor, thus resulting in cooling of the rotor and the stator.

Particularly preferably, each stator module in each case has a flux-guiding element, which is passed through the at least one stator-side coil, with the cross-sectional area of the flux-guiding element in the coil area being less than the cross-sectional area of the stator-side magnet.

If the cross sections are refined in this way, this leads to flux concentration in the area of the stator-side coil.

In a corresponding manner, it is possible for the flux-guiding stator-side element to be smaller in the coil area than in the area of its limb ends, with which it forms the interface to the rotor. This refinement as well leads to flux concentration in the coil area, but in this case it is possible to influence the air-gap field at the interface between the rotor and the stator.

In order to guide the lines of force through the stator in as optimum a manner as possible, the stator-side sections of the magnetic circuits can each be provided with at least one magnetic flux barrier, which has a higher specific magnetic reluctance than the rest of the material in the respective stator-side section. Flux barriers such as these modify the profile of the lines of force, since the lines of force cannot pass through the flux barriers, or can do so only poorly, and in consequence have to (at least predominantly) pass around the flux barriers.

Furthermore, it is considered to be advantageous for the stator-side magnet or magnets to be embedded in the flux-guiding stator-side material.

Converters are preferably used to convert the generator output voltage and output frequency, which are dependent on the propeller rotation speed.

It is also possible to incline the rotor structure in one direction or—for example half in each case—in both directions (arrow inclination) in order, inter alia, to reduce cogging torques and to positively influence the sound which is produced.

The invention will be explained in more detail in the following text with reference to exemplary embodiments; in this case, by way of example:

FIG. 1 shows one exemplary embodiment of an arrangement having a wind energy installation according to the invention, which is connected to a power transmission system,

FIGS. 2 to 19 show various exemplary embodiments of stator modules for a generator for the wind energy installation shown in FIG. 1,

FIG. 20 shows one exemplary embodiment of obliquely running teeth of a rotor for the wind energy installation shown in FIG. 1, and

FIG. 21 shows a further exemplary embodiment of obliquely running teeth of a rotor for the wind energy installation shown in FIG. 1.

For the sake of clarity, the same reference symbols are always used for identical or comparable components in the figures.

FIG. 1 shows an arrangement having a wind energy installation 10 which is connected to a power transmission system 20. The wind energy installation 10 converts wind energy to electrical energy, and feeds this into the power transmission system 20.

The wind energy installation 10 comprises a propeller 30, which may have a plurality of blades 40. In the exemplary embodiment shown in FIG. 1, the propeller 30 has three blades, however, of course, the propeller 30 may also have more or fewer blades.

The propeller 30 rotates about a shaft 50 which is connected to a generator 60 of the wind energy installation 10. If the action of the wind on the propeller 30 causes it to rotate about the shaft 50, as a result of which the generator 60 will produce electric current I, which is fed into the power transmission system 20.

By way of example, FIG. 2 shows one possible embodiment of the generator 60, illustrated partially. FIG. 2 thus shows a stator module 100 which, together with other stator modules, which will not be described in any more detail, forms a stator of the generator 60. In addition, the figure shows a section 110 of a rotor of the generator 60, which rotor will not be described in any more detail.

The reference symbol 120 in FIG. 2 indicates a magnetic circuit which, on the stator side, covers a flux-guiding element 125 of the stator module 100, a module-specific magnet 130 of the stator module 100 as well as two module-specific coils 140 and 141 of the stator module 100. At least a portion of the magnetic flux which is produced by the module-specific magnet 130 flows through the module-specific coils 140 and 141. The flux-guiding element 125 of the stator module 100 may also be referred to as the magnetic yoke of the stator module 100.

Furthermore, the magnetic circuit 120 covers a section of the rotor 110. The section of the rotor 110 forms a magnetic reluctance Rm which depends on the respective rotation angle of the rotor relative to the stator. For example, FIG. 2 shows that the rotor 110 has teeth 150 which form a low magnetic reluctance. The teeth 150 are separated from one another by gaps 160, which form a magnetic reluctance which is higher than that of the teeth 150. When the rotor 110 is now rotated with respect to the stator module 100, the total magnetic reluctance for the magnetic circuit 120 will vary periodically and will always depend on the respective rotation angle of the rotor relative to the stator.

For example, if it is assumed that the module-specific magnet 130 produces a constant magnetic field strength, then the magnetic flux which flows through the magnetic circuit 120 will therefore depend on the respective position of the rotor. If the rotor 110 is aligned as illustrated in FIG. 2, then the magnetic flux in the magnetic circuit 120 will be a maximum. In contrast, if the rotor is rotated, then the magnetic flux will decrease. The flux variation in the two module-specific coils 140 and 141 results in a voltage being induced at the conductor ends of the two coils, which can be output as electrical energy to the power transmission system 20 as shown in FIG. 1.

Furthermore, as can be seen from FIG. 2, the flux-guiding element 125 of the stator module 100 has a U-shaped cross section and has two limb ends 200 and 210, which interact with the teeth 150 and the gaps 160 in the rotor 110. The configuration of the flux-guiding element 125 with the U-shaped cross section should in this case be understood only as an example; the flux-guiding element 125 may, of course, also have different shapes, as will be explained in more detail further below in conjunction with other exemplary embodiments.

In order to achieve a smooth rotor surface, the gaps 160 may be filled with a material which has a different magnetic reluctance to that of the teeth 150. For example, the gaps 160 may be filled with plastic or a resin.

However, it is considered to be particularly advantageous for the gaps 160 to be filled only with air, as a result of which air is swirled in the gap between the rotor and the stator when the rotor rotates, and both the rotor and the stator are cooled by the airflow.

The module-specific magnet 130 may be a permanent magnet or an electromagnet.

FIG. 3 shows another exemplary embodiment for one possible refinement of the stator module 100. In the exemplary embodiment shown in FIG. 3, the module-specific magnet 130 of the stator module 100 is embedded in the material of the flux-guiding element 125. Apart from this, the exemplary embodiment shown in FIG. 3 corresponds to the exemplary embodiment shown in FIG. 2.

By way of example, FIG. 4 shows one exemplary embodiment of a stator module 100, in which there are two module-specific magnets 130 and 131. The two module-specific magnets are located at the limb ends 200 and 210 of the U-shaped flux-guiding element 125. Apart from this, the exemplary embodiment shown in FIG. 4 corresponds to the exemplary embodiment shown in FIGS. 2 and 3.

FIG. 5 shows one exemplary embodiment of a stator module 100 in which the flux-guiding, module-specific element 125 has a smaller cross-sectional area in the area of the module-specific coils 140 and 141 than in the area of the limb ends 200 and 210. Preferably, the shape of the teeth 150 in the rotor is matched to the shape and the cross section of the limb ends 200 and 210; for example, the cross sections of the limb ends and the cross sections of the teeth 150 are identical.

FIG. 6 shows one exemplary embodiment of a stator module 100 of the generator 60 in which flux is likewise concentrated in the area of the module-specific coils 140 and 141. As can be seen, the flux-guiding stator-side element 125 has a smaller cross section in the area of the module-specific coils 140 and 141 than in the curved area 126 of the flux-guiding element 125.

By way of example, FIG. 7 shows one exemplary embodiment of a stator module 100 which represents a form of combination of the exemplary embodiments shown in FIGS. 4 and 5. For example, FIG. 7 shows two module-specific magnets 130 and 131, which are arranged at the limb ends 200 and 210 of the flux-guiding stator-side element 125. The figure also shows that the cross section of the limb ends 200 and 210 and the cross section of the module-specific magnets 130 and 131 is larger than the cross section of the flux-guiding stator-side element 125 in the area of the two module-specific coils 140 and 141.

FIG. 8 shows one exemplary embodiment of a stator module 100, in which the flux-guiding element 125 of the stator module 100 is like a comb or is in the form of a comb. Preferably, the flux-guiding element 125 is a curved comb with limbs which are formed radially on the inside, of which three are annotated with the reference symbols 300, 301 and 302, by way of example, in FIG. 8.

The pole pitch of the stator module 100 and the pole pitch of the rotor are identical in the exemplary embodiment shown in FIG. 8, as a result of which the voltages induced in the module-specific coils 140, 141, 142 are either in phase or have a phase offset of 180°. Current and voltage can thus be produced for a single-phase power transmission system, by appropriate connection of the module-specific coils.

In the exemplary embodiment shown in FIG. 9, the flux-guiding, stator-side element 125 of the stator module 100 is likewise formed by a curved element with a comb-like structure, as has already been explained in conjunction with FIG. 8. In contrast to the exemplary embodiment shown in FIG. 8, however, the pole pitch between the stator and the rotor is not identical, as a result of which the voltages induced in the module-specific coils 140, 141 and 142 have a phase offset with respect to one another, depending on the pole offset between the stator and the rotor. An offset such as this makes it possible to generate polyphase, for example three-phase, currents and voltages for a polyphase, in particular three-phase, power transmission system.

FIG. 10 shows one exemplary embodiment of a stator module 100, in which the module-specific magnets 130, 131 and 132 are aligned along the longitudinal direction of the limbs 300, 301 and 302 of the flux-guiding, stator-side element 125 of the stator module 100. In this refinement, a relative rotation of the rotor relative to the stator results in a change in the direction of the lines of force within the limbs, and therefore to a phase change of the electrical voltages induced in the module-specific coils 140, 141 and 142.

FIG. 11 shows one exemplary embodiment of a stator module 100, in which flux barriers 400, which have a particularly high magnetic reluctance, are integrated in the limbs 300, 301 and 302 of the flux-guiding, stator-side element 125. The function of the flux barriers 400 is to guide the magnetic lines of force in a suitable manner within the flux-guiding, stator-side element 125 so as to achieve as high an efficiency level as possible.

FIGS. 12 and 13 use one exemplary embodiment to show how the stator modules 100 may be combined to form a complete stator 500. As can be seen, each stator module 100 in each case has two attachment pins 510, by means of which the stator modules can each be connected to adjacent stator modules, for example by brackets. It is also possible to fit an attachment ring to the attachment pins 510, which attachment ring is indicated in FIG. 13 and is annotated with the reference symbol 520, and whose ring diameter corresponds to the diameter of the stator 500.

As can also be seen from FIGS. 12 and 13, the stator modules 100 each have two outer ring segments 530 and 540, which are fitted externally to the flux-guiding element or magnetic yoke 125 of the stator module 100. By way of example, a module-specific cooling device can be integrated in the first outer ring segment 530, and is arranged indirectly or directly on the yoke outer face of the magnetic yoke 125 which is averted from the rotor.

By way of example, a converter or rectifier may be integrated in the second outer ring segment 540, which is fitted to the first outer ring segment 530, converting or rectifying an AC voltage produced by the module-specific coil or coils, and producing a module-specific AC voltage or DC voltage as the module-specific output voltage. In the exemplary embodiment shown in FIG. 13, the converters or rectifiers are each arranged on an outer face of the first ring segment 530, averted from the rotor 110 and the magnetic yoke 125, and therefore on the outer face of the module-specific cooling device, averted from the yoke outer face. The cooling device therefore advantageously cools both the internal magnetic yoke 125 and the external converter or rectifier.

By way of example, FIG. 14 shows stator modules 100 which are each equipped with two attachment pins 510 and each have an outer ring segment 530 with an integrated module-specific cooling device. The cooling device is in each case fitted to the yoke outer face of the yoke 125. However, there is no second outer ring segment with a converter or rectifier in this exemplary embodiment.

By way of example FIG. 15 shows stator modules 100 which are connected to one another by brackets, which are not illustrated in any more detail. There are no outer ring segments for cooling devices and/or converters or rectifiers in this exemplary embodiment.

By way of example, FIG. 16 shows one possible embodiment of a stator module 100 with a module-specific magnet 130 and a module-specific coil 140. The coil 140 has external electrical connections 600, by means of which the stator module 100 can be electrically connected to other stator modules.

By way of example, FIG. 17 shows one possible embodiment of a stator module 100 in which a module-specific rectifier 610 is connected to the electrical connections 600 of the module-specific coil 140. External connections 620 of the rectifier 610 are used to electrically connect the stator module 100 to other stator modules.

By way of example, FIG. 18 shows one possible embodiment of a stator module 100, in which a module-specific converter 630 is connected to the electrical connections 600 of the three module-specific coils 140. The converter 630 is formed by a module-specific rectifier 640 and a downstream module-specific inverter 650. External connections 660 of the converter 630 are used to electrically connect the stator module 100 to other stator modules. In addition, the stator module 100 has a cooling device, which is annotated with the reference symbol 670.

By way of example, FIG. 19 shows the possibility of designing a generator 60 as shown in FIG. 1 such that the rotor 110 can move externally around the stator modules 100. All the embodiment variants shown in FIGS. 2 to 18 may also be in the form of external rotors.

By way of example, FIG. 20 illustrates that the teeth 150 need not necessarily run parallel to the rotation axis 50 shown in FIG. 1. As can be seen, in the exemplary embodiment shown in FIG. 20, the teeth 150 on the rotor are provided with an oblique profile; this is because the teeth 150 run obliquely or at an angle to the rotation axis 50 of the rotor.

In a corresponding manner, the limbs of the flux-guiding, stator-side element or elements 125 of the stator modules 100 may also be aligned obliquely or at an angle to the rotation axis 50 of the generator.

By way of example, FIG. 21 shows an inclined tooth shape, in which the teeth have an arrow-shaped incline. Therefore, one section of each tooth is in each case oriented away from the rotation axis while, in contrast, a further section, adjacent thereto, of the respective tooth is once again oriented toward the rotation axis—thus forming a structure per tooth which is arrow-shaped overall—seen along the rotation axis.

LIST OF REFERENCE SYMBOLS

-   10 Wind energy installation -   20 Power transmission system -   30 Propeller -   40 Blade -   50 Shaft -   60 Generator -   100 Stator module -   110 Rotor -   120 Magnetic circuit -   125 Flux-guiding module-specific element -   126 Curved or bottom area -   130 Magnet -   131 Magnet -   132 Magnet -   140 Stator-side coil -   141 Stator-side coil -   142 Stator-side coil -   150 Teeth -   160 Gaps -   200 Limb ends -   210 Limb ends -   300 Limb -   301 Limb -   302 Limb -   400 Flux barrier -   500 Stator -   510 Attachment pin -   520 Attachment ring -   530 First ring segment -   540 Second ring segment -   600 Electrical connection -   610 Module-specific rectifier -   620 External connection -   630 Module-specific converter -   640 Module-specific rectifier -   650 Module-specific inverter -   660 External connection -   670 Cooling device -   I Current -   Rm Reluctance 

1. A wind or water energy installation for production of electrical energy having at least one propeller and at least one generator, which comprises a rotor and a stator characterized in that the stator is formed by at least two stator modules which are mechanically and electrically independent of one another and each interact with the rotor, each of the stator modules in each case comprises at least one module-specific magnet, at least one coil through which at least a portion of the magnetic flux of the magnet flows, and each of the stator modules in each case forms a module-specific magnetic circuit with the rotor, with each stator module producing a module-specific output voltage in the event of a relative movement between the rotor and the stator.
 2. The wind or water energy installation as claimed in claim 1, characterized in that the stator modules can each be removed from the generator, and fitted into it, independently of other stator modules, and can be replaced independently of other stator modules.
 3. The wind or water energy installation according to claim 1, characterized in that the stator modules each have a mounting device by means of which the distance between the respective stator module and the rotor can be adjusted on a module-specific basis.
 4. The wind or water energy installation as claimed in claim 1, characterized in that at least one of the stator modules, preferably all of the stator modules, has or have a module-specific cooling device.
 5. The wind or water energy installation as claimed in claim 4, characterized in that the stator module has a magnetic yoke, and the module-specific cooling device is arranged indirectly or directly on that yoke outer face of the magnetic yoke which is averted from the rotor.
 6. The wind or water energy installation as claimed in claim 1, characterized in that at least one of the stator modules, preferably all of the stator modules, has or in each case have a converter or rectifier, which converts or rectifies an AC voltage produced by the module-specific coil or coils, and produces a module-specific AC voltage or DC voltage as the module-specific output voltage.
 7. The wind or water energy installation as claimed in claim 6, characterized in that the converter or rectifier is arranged on an outer face of the module-specific cooling device which is averted from the rotor and the yoke outer face.
 8. The wind or water energy installation as claimed in claim 1, characterized in that the stator modules of the stator are physically identical.
 9. The wind or water energy installation as claimed in claim 1, characterized in that, on its surface facing the stator modules, the rotor has a magnetic reluctance (Rm), which is dependent on its respective rotation angle, such that the magnitude of the magnetic flux in the coils of the stator modules is dependent on the respective rotation angle of the rotor, and varies during rotation of the rotor.
 10. The wind or water energy installation as claimed in claim 1, characterized in that the magnets of the stator modules are permanent magnets.
 11. The wind or water energy installation as claimed in claim 1, characterized in that the arrangement of the stator modules around the rotation axis of the rotor is rotationally symmetrical.
 12. The wind or water energy installation as claimed in claim 1, characterized in that, on its surface facing the stator modules, the rotor has teeth which extend radially in the direction of the stator modules.
 13. The wind or water energy installation as claimed in claim 12, characterized in that the intermediate space between adjacent teeth is entirely or partially filled with a material which has a higher magnetic reluctance than the material of the teeth.
 14. The wind or water energy installation as claimed in claim 1, characterized in that the rotor is arranged externally around the stator or within the stator.
 15. The wind or water energy installation as claimed in claim 1, characterized in that the propeller is connected to the rotor of the generator such that they rotate together. 